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![STEPS OF SOLUTIONS:-
• L= ℎ′! + 𝑙′!
L
l’
h’
h
Where:-
h : height of form (ft) [m]
h’: height of top of strut (ft) [m]
L : length of strut (ft) [m]
l’: horizontal distance form the bottom of strut (ft) [m]](https://image.slidesharecdn.com/designofbracing-200318013644/85/Design-of-bracing-3-320.jpg)
![Strut Load per foot of form
• P’=
"∗!∗$
%!∗!&
Where:-
P : strut load per foot of form (lb/ft) [kN/m]
H : lateral load at top of form (lb/ft) [kN/m]
h : height of form (ft) [m]
h’: height of top of strut (ft) [m]
L : length of strut (ft) [m]
l’: horizontal distance from form to bottom of strut (ft) [m]](https://image.slidesharecdn.com/designofbracing-200318013644/85/Design-of-bracing-4-320.jpg)
Design of bracing
- 1. CB523 BRACING DESIGN ENG. ESRAAHUSSEIN MOHAMED
- 2. BRACING: • IS ASTRUCTURAL MEMBER USED TO SUPPORT ANOTHER. • IT USED TO RESIST THE MOVEMENT OF FORMWORK AND WIND LOADS. Bracer
- 3. STEPS OF SOLUTIONS:- •L= ℎ′! + 𝑙′! L l’ h’ h Where:- h : height of form (ft) [m] h’: height of top of strut (ft) [m] L : length of strut (ft) [m] l’: horizontal distance form the bottom of strut (ft) [m]
- 4. Strut Load perfoot of form • P’= "∗!∗$ %!∗!& Where:- P : strut load per foot of form (lb/ft) [kN/m] H : lateral load at top of form (lb/ft) [kN/m] h : height of form (ft) [m] h’: height of top of strut (ft) [m] L : length of strut (ft) [m] l’: horizontal distance from form to bottom of strut (ft) [m]
- 5. • ! " < 50 • ! " > 50 Safe UnSafe Strut Lnew= " # L/2 L/2 Check of Buckling:- D L
- 6. Allowable Compressive Stress: •FC ’=".$ % ( ! " )# “PSI” <FC <FT Safe
- 7. Maximum Allowable CompressiveForce: • P = B*D*FC ’ Maximum Strut Spacing: • S = ⁄( () “Lb” “ft”
- 8. EXAMPLE:- v Determine themaximum spacing of 2”x4” lateral braces for the wall form of 8 ft high. Lateral wood bracing will be attached at a height of 6ft above the form bottom and anchored 5ft away from the bottom of the form. Design wind load is 25 psf. - Wood charactesrstics: Fc = 850 PSI, Ft = 725 PSI, E =1,400,000 PSI h= 8ft h’= 6ft l’= 5ft Solution:- L= ℎ′! + 𝑙′! = 6! + 5! = 7.81ft P’= " ∗ $ ∗ % &! ∗ $' = ()) ∗ * ∗ +.*( - ∗ . = 208.27 lb/ft L 5ft 6ft 8ft
- 9. h= 8ft àFrom(Table 13-3) H=100lb/ft at least $∗/0 ! = *∗!- ! = 100lb/ft P’= " ∗ $ ∗ % &! ∗ $' = ()) ∗ * ∗ +.*( - ∗ . = 208.27 lb/ft % 1 = +.*( ∗(! (.- = 62.48 > 50 Lnew= +.*( ∗(! ! = 46.86 in %!"# 1 = 2..*. (.- = 31.24 < 50 Un Safe Safe
- 10. - Wood charactesrstics:Fc= 850 PSI, Ft = 725 PSI, E =1,400,000 PSI • Fc ’= ).3 ∗(,2)),))) ( "#.%# &.' )( = 430.355 PSI <Fc= 850PSI <Ft=725PSI • P = 3.5 * 1.5 * 430.355= 2259.264 Lb • S = 7 7' = !!-8.!.2 !)*.!+ = 10.85 ft “ Safe ”
- 11.